Putting video inside text with track mattes in Video by Zaweba
Use a track matte in Video by Zaweba to show a clip only inside text, a shape or a logo on another track, using alpha or brightness, or the inverse.
Video inside text is one of those effects that looks complicated and turns out not to be. Big letters across the screen, with footage playing inside each one, is done with a track matte. Video by Zaweba lets any clip use another track's picture as its matte.
How a track matte works
A matte is a picture that decides where another picture shows. With a track matte, a clip shows only inside the picture on another track. Where the matte has something, the clip shows. Where it has nothing, the clip is hidden.
The matte can be read in two ways. Alpha uses the matte's transparency: anywhere the matte is solid, the clip shows, and anywhere it is see through, the clip is hidden. That suits text, shapes and logos with transparent backgrounds. Brightness uses how light the matte is: white areas show the clip, black areas hide it, and greys show it partly. That suits black and white artwork, gradients and footage used as a matte.
Either way can be inverted, so the clip shows outside the matte instead of inside it. That cuts text out of a picture, leaving holes in the shape of the letters.
The matte track
The matte track is hidden by default. That is what you want almost every time: the text or shape is there only to shape the clip, not to appear itself. You see the result, the clip inside the shape, without the matte being drawn on top.
To see the matte itself while you work, there is a "show the matte" effect, which displays it so you can check its shape and position.
Putting video inside text
Make a title with big, bold letters. Thick typefaces work best because there is more room inside each letter for the video to show. Put it on a track. Put the footage on another track and set its track matte to the title's track, using alpha. The footage now shows only inside the letters.
Place something behind on a lower track, a plain colour or a blurred version of the same footage, so the area outside the letters is not empty.
Animate it. Scale the title up slowly so the letters grow, or move the footage inside them. Because the matte is just a clip, every keyframe tool works on it.
Other jobs
Video inside a logo. Use a logo with a transparent background as the matte.
Shape reveals. Animate a shape on the matte track growing from small to full frame, and the clip appears through it.
Soft wipes. Use a gradient with brightness, and animate it across, for a soft edged reveal from one shot to another.
Cut out lettering. Invert the matte to punch text out of a picture, letting what is below show through.
When the effect disappoints
Thin text is the usual disappointment. Fine letters leave little room for the video, and it reads as coloured text. Use a heavy typeface and make it large.
Choosing alpha for a matte with no transparency is another. If a title sits on a solid background, alpha will see the whole frame as solid. Use brightness, or a title with a transparent background.
Forgetting what lies below is the third. With the clip only inside the letters, the rest of the frame shows the tracks underneath, which may be empty. Add a background.
Mattes or masks
Track mattes sit alongside masks, SVG masks and mask tracking in Video by Zaweba. Masks are drawn on the clip itself; track mattes use another clip, which means the shape can be a full title with its own animation, a moving video, or anything else you can put on a track. For video inside words or logos, they are the simplest route.
